Calorie Calculator

Your total daily energy expenditure (TDEE) is the number of calories your body burns in a full day, including exercise and daily movement. The calculation starts with basal metabolic rate (BMR) — calories burned at complete rest — then multiplies by an activity factor. The Mifflin-St Jeor BMR formula is: men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 5; women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. TDEE = BMR × activity multiplier.

Take a 30-year-old man weighing 80 kg and 180 cm tall with moderate activity. His BMR = 10(80) + 6.25(180) − 5(30) + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal/day at rest. Moderate activity uses a multiplier of 1.55, so TDEE = 1,780 × 1.55 ≈ 2,759 kcal/day. Eating roughly this amount maintains current weight; eating 300–500 kcal below it supports gradual fat loss of about 0.25–0.5 kg per week.

Activity multipliers represent typical weekly exercise patterns. Sedentary (little or no exercise) uses 1.2. Lightly active (1–3 days/week) uses 1.375. Moderately active (3–5 days/week) uses 1.55. Very active (6–7 days/week) uses 1.725. Extra active (physical job plus daily training) uses 1.9. Choose the level that honestly reflects your average week, not your most intense one — overestimating activity is a common reason calorie targets fail.

Weight change follows the energy balance principle: roughly 3,500 kcal equals about 0.45 kg (1 lb) of body fat. A deficit of 500 kcal per day theoretically produces about 0.45 kg loss per week, though real-world results vary with water retention, muscle changes, and metabolic adaptation. For muscle gain, a surplus of 200–300 kcal above TDEE supports lean gains while limiting excess fat storage.

This calculator combines BMR estimation with your selected activity level to return maintenance calories plus optional targets for weight loss or gain. Pair the result with the macro calculator to split those calories into protein, carbohydrates, and fat for a complete nutrition plan.